Leptin is a recently identified protein that affects appetite and energy expenditure. Diseases or altered physiological states (diabetes mellitus, obesity, Cushing's syndrome, and pregnancy) display altered leptin concentrations. The role and regulation of leptin in these conditions or even in healthy people is not completely understood. We propose studying the changes in leptin and possible regulating hormones (insulin, cortisol, and DHEA) in: (1) normal women; (2) diabetic women; (3) normal, pregnant women; and (4) diabetic, pregnant women in order to gain a better understanding of how leptin functions and is regulated. Subjects will fast overnight, have a fasting blood drawn, eat a breakfast provided to them, and have a post-prandial blood sample drawn two hours later. Plasma will be assayed for leptin, cortisol, DHEA, insulin, and glucose.